In the 1990s, while reading a book about Theravada Buddhism, I came across a quotation from one of the commentaries that went something like this: "The Buddha loves all beings equally as he loves his own son, even Dhanapala, even Angulimala, even Devadatta." (This is an approximation, of course.) I have been unable to remember the title of the book it was in and googling hasn't helped me locate the quotation. Does anyone have the exact quotation and the source? It is important to me because it addresses the love of dangerous, hostile beings.

To the murderer Devadatta,To the robber Aṅgulimāla,To Dhanapāla [the elephant], and to Rāhula too —The Sage is neutral to them all.(Ap.i.47; Mil.410; DhA.i.146)

The Apadāna and the Theragāthā Atthakathā attribute the verse to Ven. Upāli. The Milindapañha attributes it to Ven. Sāriputta. In the Dhammapada Atthakathā it is spoken by the Buddha, but with samako ("neutral") replaced with samamānaso ("neutral in mind").

To the murderer Devadatta,To the robber Aṅgulimāla,To Dhanapāla [the elephant], and to Rāhula too —The Sage is neutral to them all.(Ap.i.47; Mil.410; DhA.i.146)

The Apadāna and the Theragāthā Atthakathā attribute the verse to Ven. Upāli. The Milindapañha attributes it to Ven. Sāriputta. In the Dhammapada Atthakathā it is spoken by the Buddha, but with samako ("neutral") replaced with samamānaso ("neutral in mind").